https://bugs.chromium.org/p/chromium/issues/detail?id=760373

Traceback (most recent call last):
  File "/usr/lib/python2.7/runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/lib/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/usr/local/google/home/armax/Dev/lab_tools/infra_virtualenv/venv/cros_venv/scripts/create_venv.py", line 46, in <module>
    main()
  File "/usr/local/google/home/armax/Dev/lab_tools/infra_virtualenv/venv/cros_venv/scripts/create_venv.py", line 35, in main
    print(venv.ensure())
  File "/usr/local/google/home/armax/Dev/lab_tools/infra_virtualenv/venv/cros_venv/venvlib.py", line 174, in ensure
    self._check_or_create()
  File "/usr/local/google/home/armax/Dev/lab_tools/infra_virtualenv/venv/cros_venv/venvlib.py", line 182, in _check_or_create
    self._create()
  File "/usr/local/google/home/armax/Dev/lab_tools/infra_virtualenv/venv/cros_venv/venvlib.py", line 191, in _create
    logfile=logfile)
  File "/usr/local/google/home/armax/Dev/lab_tools/infra_virtualenv/venv/cros_venv/venvlib.py", line 282, in _create_venv
    _log_check_call(command, logfile=logfile)
  File "/usr/local/google/home/armax/Dev/lab_tools/infra_virtualenv/venv/cros_venv/venvlib.py", line 304, in wrapped_command
    call_func(args, stdout=logfile, **kwargs)
  File "/usr/lib/python2.7/subprocess.py", line 535, in check_call
    retcode = call(*popenargs, **kwargs)
  File "/usr/lib/python2.7/subprocess.py", line 522, in call
    return Popen(*popenargs, **kwargs).wait()
  File "/usr/lib/python2.7/subprocess.py", line 710, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1327, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory
ERROR: Failed to set up a virtualenv.

This isn't very clear, but it's because virtualenv is not installed.